Hi Miha, You certainly need exposure compensation when using extension tubes and using an off-camera meter. With TTL I guess it depends on the precise geometry of the camera, and the position and size of the exit pupil of the lens system. With true off-the-film systems such as used in the old Olympus OM2, & OM10 my guess is that TTL will work fine (without any special compensation), but I'm not too surprised that the systems involving sensors located in the prism area or similar where imaged light is measured, may give a problem. There is a different possibility and that is stray light getting in to your camera's metering area through the eyepiece. In macro work this could be more of a problem than normally, due to the lower intensity from using tubes. (In normal use my EOS3 frequently indicates a slightly shorter exposure as I take my eye away from the viewfinder, and returns to what it was, if I return my eye and exclude extraneous light.)
M Stewart Milton Keynes, UK ----- Original Message ----- From: Miha Valencic <[EMAIL PROTECTED]> To: EOS mailing list <[EMAIL PROTECTED]> Sent: Monday, February 04, 2002 9:55 AM Subject: EOS Exposure factors for extension tubes > Hi! > > I've been using Kenko extension tubes ans received underexposed slides. Now, I thought that TTL will take care of everything -- well, I was wrong. > > I found (Kenko site) that I should've used exposure compenstaion and there are stated exposure factors. But what do they mean? > > For 20 mm ext. tube its. 2.0. Does this mean 2 f stops? And for 56 mm it is 4.5 - 5.0, depending on the focusing distance. Does this mean 4 to 5 f stops? > > Regards, > > IVI. * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
